This is an English version of my written technical article. (Please see original URL for reference figures)

IP datacast (IPDC: IP Data Cast) is a technology for carrying multimedia file data by broadcasting IP packets on broadcasting and communication to various device terminals simultaneously. NTT DATA is working on the development and standardization of IP datacast technology that realizes new services in broadcasting and communications fields. Here we introduce the technical overview and features of IPDC, application examples, latest technologies under development and future prospects.

Background

New business beyond the traditional broadcasting and communication service framework such as multimedia broadcasting for mobile terminals that utilizes the free bandwidth accompanying digitization of broadcasting and dissemination of video content distribution for smartphones and tablet terminals by wireless broadband communication By deployment, cooperation between broadcasting and communication is accelerating. Against this backdrop, NTT DATA is actively working on the development and standardization of IP datacast (IPDC: IP DataCast) as one means of realizing a new service in which broadcasting and communication cooperate . Here we introduce IPDC technical overview and features, NOTTV’s application to shift time broadcasting, distribution of disaster prevention / disaster information and live streaming.

Technical overview and characteristics of IPDC

IPDC is a technology to transmit multimedia files (text, images, sounds, images, etc.) simultaneously by broadcasting IP packets for broadcasting and communication to various device terminals. By using such simultaneous broadcasting technology, even if the number of terminals increases, there is an advantage that congestion at traffic concentration can be avoided. Also, in the case of broadcast waves, it is possible to deliver a large variety of large files than digital broadcast data broadcasts.

Utilizing the features of this technology, multimedia content distribution in corporate / media fields, simultaneous broadcasting of emergency bulletins in the event of a disaster and simultaneous distribution of regional administrative information, distribution of control programs to vending machines and the like Usage scenes in the M2M (Machine to Machine) field that performs device control itself are assumed (Fig. 1).

The IPDC’s protocol stack is shown in Figure 2. In IPDC, it is necessary to deliver the file to the terminal completely in one direction. In order to realize this, in addition to the repeated transmission by the FLUTE (File Delivery over Unidirectional Transport: RFC 3926) protocol, AL - FEC (Application Layer Forward Error Correction) , We have established a mechanism that allows files to be delivered to terminals even if packets are lost during transmission. LDPC-Staircase (Low Density Parity Check: RFC 5170) is often used for AL-FEC.

Figure 3 shows the procedure for sending and receiving data by IPDC. After dividing the file into units called source symbols of about 1 KB, FEC symbols for error correction are generated from the combination of symbols and transmitted together with the source symbols. This makes it possible to restore the missing source symbols from the computation of the received symbol combination even if all source symbols do not arrive due to the break of the broadcast wave or loss of the communication packet.

Solution to smartphone broadcast station “NOTTV”

In the multimedia broadcast “NOTTV” for smartphones started in April 2012, contents such as images and newspapers are distributed as “shift time broadcasting service”. This service is realized by IPDC, and NTT DATA has commercialized the server which simultaneously sends large capacity files of up to 4 GB in multiple sessions and the receiving client in the world for the first time.

Figure 4 shows the transmission / reception mechanism of the shift time broadcasting service. “IPDC transmission server” sends metadata describing information on video / e-book / game / content by FLUTE / ALFEC technology. There is also a function to convert IP packets into data to be placed on broadcast waves. “IPDC Receiving Engine” receives content transmitted by broadcast waves and restores it in a form that subscribers can view. There is also a mechanism to complement the missing part by communication when content can not be completely received by the broadcast wave. “Metadata management” creates and manages metadata related to contents, and provides a mechanism for subscribers to search. In addition, we provide content protection based on viewer’s information as other mechanisms, as well as contractor management.

Demonstration experiment of disaster information distribution by V-Low multimedia broadcasting

The V-Low (VHF - Low) multimedia broadcasting is scheduled to start service around the summer of 2014. In that case, broadcasting will be done in units of 7 regional blocks nationwide. In addition to radio audio broadcasting, it is considered to provide services such as distribution of radio program-linked contents using IPDC, distribution of traffic information, distribution of advertisements and e-books in limited areas.

V-Low multimedia broadcasting is attracting attention as a new medium for information distribution in emergencies, such as disasters, due to the Great East Japan Earthquake. Disaster management radio in municipalities is a common way of communicating information in emergencies, but it is difficult to hear depending on location and weather, information can not be confirmed later, etc. There are problems. In order to compensate for this drawback, the use of IPDC is being studied, so that IPDC can send the file of disaster information, evacuation order, evacuation life information at the time of emergency to the user’s terminal, so that the terminal can confirm the information at any time It becomes (Figure 5). NTT DATA developed an IPDC solution for emergency information distribution and conducted a demonstration experiment using radio waves of V-Low multimedia broadcasting in the coastal area of Miyagi prefecture in FY2012.

In the field trials, we measured data transmission time assuming three types of emergency information. The results are shown in the table. The time from the input of data at the IPDC transmission server to the display of information at the receiving terminal was measured for information such as emergency earthquake early warning and evacuation order with high urgency, the average of 14 times was 6.9 seconds. According to the standard of disaster prevention administrative radio, it is supposed to be within 8 seconds from the operation console to the ringing of the outdoor speaker, so it is considered possible to substitute.

Development of IPDC live streaming by MPEG-DASH technology

MPEG-DASH (Dynamic Adaptive Streaming over HTTP) is the latest international standard that realizes streaming delivery of moving pictures and sound by HTTP protocol for various device terminals. NTT DATA has developed a solution that realizes live streaming by sending and receiving movies and sound files in segment format of several seconds supported by MPEG - DASH via IPDC. Furthermore, in order to develop this technology, LDGM (Low Density Generator Matrix) code which is AL-FEC technology being developed at NTT Future Net Innovation Laboratories is implemented on the IPDC live streaming server and client terminal and evaluated . In addition, we are also evaluating receiving NTT docomo HEVC (High Efficiency Video Coding) decoding software compliant with H.265 standard, which is the next generation video compression technology.

Figure 6 shows the mechanism of IPDC live streaming transmission and reception. The live image from the camera is compressed by dividing it into segment files in seconds by the encoder · segmenter. The IPDC live streaming server converts the segment file to the source / FEC symbol by FLUTE / AL-FEC technology and sends it. The IPDC live streaming client restores the segment file from the received source · FEC symbol and accumulates it in the HTTP server. The player sequentially retrieves the video you want to play from the HTTP server, retrieves the segment file and plays the video. In the experimental environment of NTT data, it is expected to be able to transmit and receive with a delay of about 6 seconds when distributing the full HD picture quality in H.264 format

Wi-Fi Area Broadcast Content Delivery System

NTT DATA is developing an area broadcast type content distribution solution using Wi-Fi and IPDC of the wireless LAN standard. It is not a one-to-one PULL type (pseudo PUSH) distribution by conventional unicast, but realizes a one-to-many complete PUSH type multicast broadcasting type content delivery service with no congestion. This makes it possible for O2O (Online to Offline) * applications such as relaying live images at stadiums and event sites, disaster prevention such as evacuation guidance at disasters, discount coupon delivery at restaurants, Content delivery can be realized.

NTT DATA plans to carry out field trials in collaboration with local governments to evaluate the usefulness of simultaneous data distribution of local information and disaster prevention information from local governments to local residents by Wi-Fi multicast.

Future prospect for creating next-generation broadcasting and communication services

LTE enhanced eMBMS (enhanced Multimedia Broadcast Multicast Service) has been standardized as a service that realizes simultaneous multicast delivery of large volume data to a large number of users using a mobile phone network, and demonstration experiments in Verizon, Korea Has begun. There is no such movement in each mobile carrier in the country, but it is expected to be realized by big event, live broadcast at the stadium and contents distribution. eMBMS is adopting FLUTE / AL-FEC technology as well as IPDC, it has high technology affinity, so NTT DATA is paying attention to trends as a future solution deployment destination.

In multiscreen broadcasting, services that transmit program related contents via IPDC in synchronization with the progress of TV broadcast programs and display them automatically on smartphones and tablet terminals are being studied. There is also a move to adopt IPDC for data transmission even in the next generation version of area broadcasting service. NTT DATA will continue to promote the standardization of IPDC technology and plan and develop new services and solutions in both broadcasting and communication fields.